Computer interface or control input device for laparoscopic surgical instrument and other elongated mechanical objects

ABSTRACT

An apparatus for interfacing the movement of a shaft with a computer includes a support, a gimbal mechanism having two degrees of freedom, and three electromechanical transducers. When a shaft is engaged with the gimbal mechanism, it can move with three degrees of freedom in a spherical coordinate space, where each degree of freedom is sensed by one of the three transducers. A fourth transducer can be used to sense rotation of the shaft around an axis. The method includes the steps of defining an origin in 3-dimensional space, physically constraining a shaft in the 3-dimensional space such that a portion of the shaft always intersects the origin and such that a portion of the shaft extending beyond the origin defines a radius in a spherical coordinate system, transducing a first electrical signal related to a first angular coordinate of the radius with a first transducer, transducing a second electrical signal related to a second angular coordinate with a second transducer, transducing a third electrical signal related to the length of the radius with a third transducer, and coupling the transducers to a computer.

BACKGROUND OF THE INVENTION

This invention relates generally to human/computer interface devices,and more particularly to computer input devices such as mice,trackballs, etc.

Virtual reality computer systems provide users with the illusion thatthey are part of a "virtual" environment. A virtual reality system willtypically include a personal computer or workstation, specializedvirtual reality software, and virtual reality I/O devices such as headmounted displays, pointer gloves, 3D pointers, etc.

For example, a virtual reality computer system can allow adoctor-trainee or other human operator or user to "manipulate" a scalpelor probe within a computer-simulated "body", and thereby perform medicalprocedures on a virtual patient. In this instance, the I/O device istypically a 3D pointer, stylus, or the like. As the "scalpel" or "probe"moves within the body image displayed on the screen of the computersystem, results of such movement are updated and displayed so that theoperator can gain the experience of such a procedure without practicingon an actual human being or a cadaver.

For virtual reality systems to provide a realistic (and thereforeeffective) experience for the user, sensory feedback and manualinteraction should be as natural as possible. As virtual reality systemsbecome more powerful and as the number of potential applicationsincreases, there is a growing need for specific human/computer interfacedevices which allow users to interface with computer simulations withtools that realistically emulate the activities being represented withinthe virtual simulation. Such procedures as laparoscopic surgery,catheter insertion, and epidural analgesia should be realisticallysimulated with suitable human/computer interface devices if the doctoris to be properly trained.

While the state of the art in virtual simulation and medical imagingprovides a rich and realistic visual feedback, there is a great need fornew human/computer interface tools which allow users to perform naturalmanual interactions with the computer simulation. For medicalsimulation, there is a strong need to provide doctors with a realisticmechanism for performing the manual activities associated with medicalprocedures while allowing a computer to accurately keep track of theiractions.

There are number of devices that are commercially available forinterfacing a human with a computer for virtual reality simulations.There are, for example, such 2-dimensional input devices such as mice,trackballs, and digitizing tablets. However, 2-dimensional input devicestend to be awkward and inadequate to the task of interfacing with3-dimensional virtual reality simulations. In contrast, a 3-dimensionalhuman/computer interface tool sold under the trademark Immersion PROBE™is marketed by Immersion Human Interface Corporation of Palo Alto,Calif., and allows manual control in 3-dimensional virtual realitycomputer environments. A pen-like stylus allows for dexterous3-dimensional manipulation, and the position and orientation of thestylus is communicated to a host computer. The Immersion PROBE has sixdegrees of freedom which convey spatial coordinates (x, y, z) andorientation (role, pitch, yaw) of the stylus to the host computer.

While the Immersion PROBE is an excellent 3-dimensional interface tool,it may be inappropriate for certain virtual reality simulationapplications. For example, in some of the aforementioned medicalsimulations three or four degrees of freedom of a 3-dimensionalhuman/computer interface tool is sufficient and, often, more desirablethan five or six degrees of freedom because it more accurately mimicsthe real-life constraints of the actual medical procedure. Therefore, aless complex, more compact, lighter weight, lower inertia and lessexpensive alternative to six degree of freedom human/computer interfacetool is desirable for certain applications.

SUMMARY OF THE INVENTION

The present invention provides a 3-dimensional human/computer interfacetool which is particularly well adapted to virtual reality simulationsystems that require fewer degrees of freedom, e.g. two, three, or fourdegrees of freedom. The present invention therefore tends to be lesscomplex, more compact, lighter weight, less expensive, more reliable andhave less inertia than 3-dimensional human/computer interface tools ofthe prior art having more degrees of freedom.

The present invention is directed to a method and apparatus forproviding an interface between a human and a computer. The human end ofthe interface is preferably a substantially cylindrical object such as ashaft of a surgeon's tool, a catheter, a wire, etc. Alternatively, itcan comprise a pool cue, a screw driver shaft, or any other elongatedobject that is manipulated in 3-dimensional space by a human operator.In certain embodiments of the present invention, the computer developssignals to provide force feedback to the object. For example, a twistingor resisting force can be imparted on the object to provide haptic orforce feedback of a medical procedure being performed in a virtualreality simulation.

An apparatus for interfacing with a electrical system includes asupport, a gimbal mechanism coupled to the support, and preferably threeelectromechanical transducers, although certain embodiments (e.g. foruse with catheters) may require only two electromechanical transducers.The gimbal mechanism has a base portion which is rotatably coupled tothe support to provide a first degree of freedom, and an objectreceiving portion rotatably coupled to the base portion to provide asecond degree of freedom. A first electromechanical transducer iscoupled between the support and the base portion, a secondelectromechanical transducer is coupled between the base portion and theobject receiving portion, and a third electromechanical transducer iscoupled between the object receiving portion and an intermediate portionof an elongated object that is at least partially disposed within theobject receiving portion. The third electromechanical transducer isassociated with a third degree of freedom. Therefore, each of the threetransducers are associated with a degree of freedom of movement of theobject when it is engaged with the object receiving portion of thegimbal mechanism.

More specifically, an apparatus for interfacing an operator manipulableshaft with a computer includes a support, a gimbal mechanism, and foursensors. The gimbal mechanism preferably includes a U shaped baseportion having a base and a pair of substantially parallel legsextending therefrom, where the base of the U shaped base portion isrotatably coupled to the support, and a shaft receiving portionpivotally coupled between the legs of the base portion. The shaftreceiving portion includes a translation interface and a rotationinterface that engage the shaft when it is engaged with an aperture ofthe shaft receiving portion. The base portion rotates around a firstaxis and the shaft receiving portion rotates around a second axissubstantially perpendicular to the first axis, such that an axis of theshaft defines a radius in a spherical coordinate system having an originat an intersection of the first axis and the second axis. A first sensoris coupled between the support and the U shaped base portion to providea first output signal, a second sensor is coupled between the U shapedbase portion and the shaft receiving portion to produce a second outputsignal, a third sensor is coupled to the translation interface toproduce a third output signal, and a fourth sensor is coupled betweenthe rotation interface and the object to produce a fourth output signal.The output signals are preferably coupled to an input of a computer byan electronic interface.

In an alternative embodiment of the present invention a first actuatoris coupled between the support and the U shaped base portion to producea movement therebetween in response to a first input electrical signal,a second actuator is coupled between the U shaped base portion and theshaft receiving portion to produce a movement therebetween in responseto a second input electrical signal, a third actuator is coupled to thetranslation interface to produce a mechanical movement of the elongatedcylindrical object relative to the shaft receiving portion in responseto a third input electrical signal, and a fourth actuator is coupled tothe rotation interface to produce a mechanical movement of the elongatedcylindrical object relative to the shaft receiving portion in responseto a fourth input electrical signal.

A method for providing a human/computer interface includes the steps of:(a) defining an origin in a 3-dimensional space; (b) physicallyconstraining a shaft that can be grasped by an operator such that aportion of the object always intersects the origin and such that theportion of the object extending past the origin defines a radius in aspherical coordinate system; (c) transducing a first electrical signalrelated to a first angular coordinate of the radius in the sphericalcoordinate system with a first transducer; (d) transducing a secondelectrical signal related to a second angular coordinate of the radiusin the spherical coordinate system with a second transducer; (e)transducing a third electrical signal related to the length of theradius with a third transducer; and (f) electrically coupling thetransducers to a computer system to provide a human/computer interface.The method can further include the step of transducing a fourthelectrical signal related to a rotation of the shaft around an axis witha fourth transducer. The transducers are either sensors, actuators, orbi-directional transducers which can serve as either input or sensors.

It will therefore be appreciated that a human/computer interface of thepresent invention includes a support, a gimbal mechanism coupled to thesupport, and an elongated shaft engaged with the gimbal mechanism andhaving a grip area that can be grasped by a hand of an operator. Thegimbal mechanism has a base portion rotatably coupled to the support,and a shaft receiving portion rotatably coupled to the base. A firstsensor is coupled between the support and the base portion, a secondsensor is coupled between the base portion and the shaft receivingportion, and a third sensor is coupled between the shaft receivingportion and an intermediate portion of the shaft. The three sensors arecoupled to an input of a computer to provide the human/computerinterface. Preferably, the interface further includes a fourth sensorcoupled between the shaft receiving portion and an intermediate portionof the shaft, where the third sensor is a translation sensor and thefourth sensor is a rotation sensor.

The advantage of the present invention is that a 3-dimensionalhuman/computer interface tool is provided which has the three or fourdegrees of freedom available that are desirable for many virtual realitysimulation applications. The mechanism of the present invention isrelatively straight-forward allowing for low cost production and highreliability. Furthermore, since the human/computer interface tool of thepresent invention is constrained from movement along at certain degreesof freedom, it can more accurately simulate the use of tools and otherelongated mechanical objects which are similarly constrained.Importantly, the present interface is of low inertia since the primarymass of the interface is located at the pivot point. This, along withthe light weight of the interface, makes the interface less fatiguing touse.

In another embodiment of the present invention a human/computerinterface tool is provided which is provided with only two degrees offreedom. This is particularly advantageous when the shaft is flexible,such as with very thin shafts, wires, catheters, and the like. With, forexample, catheters, it is only necessary to provide two degrees offreedom (i.e. in-and-out, and rotation) and, therefore, sensors and/oractuators for the other degrees of freedom do not need to be provided.

These and other advantages of the present invention will become apparentto those skilled in the art upon a reading of the following descriptionsof the invention and a study of the several figures of the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a virtual reality system which employsan apparatus of the present invention to interface a laparoscopic toolhandle with a computer system;

FIG. 2 is a perspective view of an apparatus for mechanicallyinterfacing an elongated mechanical object with an electrical system inaccordance with the present invention;

FIG. 2a is a perspective view of an alternative translation interfaceused for wires, catheters, and the like;

FIG. 3 is a front elevation view of the apparatus of FIG. 2 illustratinga laparoscopic tool engaged with an object receiving portion of thepresent invention;

FIG. 4 is a side elevation similarly showing a laparoscopic tool engagedwith the object receiving portion of the present invention;

FIG. 5 is a top plan view also illustrating the engagement of alaparoscopic tool with the object receiving portion of the presentinvention;

FIG. 6 is a pictorial view illustrating the four degrees of freedomenjoyed with the mechanism of the present invention;

FIG. 7 illustrates a first embodiment of an input sensor;

FIG. 8 illustrates a modified laparoscopic tool handle for the use ofthe present invention;

FIG. 8a is a cross-section taken along line 8a--8a of FIG. 8;

FIG. 9 is a perspective view of a sensor in accordance with the presentinvention;

FIG. 9a is a sectional view taken along line 9a--9a of FIG. 9.;

FIG. 9b is a perspective view of an alternative sensing wheel used forwires, catheters, and the like;

FIG. 10 a perspective view of and alternative sensor mechanism of thepresent invention;

FIG. 10a is a cross sectional view taken along line 10a--10a of FIG. 10;

FIG. 11 is a perspective view of another alternative sensor of thepresent invention; and

FIG. 11a sectional view taken along line 11a--11a of FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, a virtual reality system 10 includes a human/computerinterface apparatus 12, a electronic interface 14, and a computer 16.The illustrated virtual reality system 10 is directed to a virtualreality simulation of a laparoscopic surgery procedure. The software ofthe simulation is not a part of this invention and thus will not bediscussed in any detail. However, such software is commerciallyavailable as, for example, Teleos™ from High Techsplanations ofRockville, Md. Suitable software drivers which interface such simulationsoftware with computer input/output (I/O) devices are available fromImmersion Human Interface Corporation of Palo Alto, Calif.

A laparoscopic tool 18 used in conjunction with the present invention ismanipulated by an operator and virtual reality images are displayed on ascreen 20 of the digital processing system in response to suchmanipulations. Preferably, the digital processing system is a personalcomputer or workstation, such as an IBM-PC AT or Macintosh personalcomputer, or a SUN or Silicon Graphics workstation. Most commonly, thedigital processing system is a personal computer which operates underthe MS-DOS operating system in conformance with an IBM PC AT standard.

The human/interface apparatus 12 as illustrated herein is used tosimulate a laparoscopic medical procedure. In addition to a standardlaparoscopic tool 18, the human/interface apparatus 12 includes abarrier 22 and a standard laparoscopic trocar 24. The barrier 22 is usedto represent portion of the skin covering the body of a patient. Trocar24 is inserted into the body of the patient to provide an entry andremoval point from the body of the patient for the laparoscopic tool 18,and to allow the manipulation of the laparoscopic tool 18 within thebody of the patient while minimizing tissue damage. Laparoscopic tools18 and trocars 24 are commercially available from sources such as U.S.Surgical of Connecticut. Preferably, the laparoscopic tool 18 ismodified such that the end of the tool (such as any cutting edges) areremoved, leaving only the handle and the shaft. The end of thelaparoscopic tool 18 is not required for the virtual reality simulation,and is removed to prevent any potential damage to persons or property. Agimbal apparatus 25 is shown within the "body" of the patient in phantomlines.

The laparoscopic tool 18 includes a handle or "grip" portion 26 and ashaft portion 28. The shaft portion is an elongated mechanical objectand, in particular, is an elongated cylindrical object. The presentinvention is concerned with tracking the movement of the shaft portion28 in three-dimensional space, where the movement has been constrainedsuch that the shaft portion 28 has only three or four free degrees ofmotion. This is a good simulation of the real use of a laparoscopic tool18 in that once it is inserted into a trocar 24 and through the gimbalapparatus 25, it is limited to about four degrees of freedom. Moreparticularly, the shaft 28 is constrained at some point of along itslength such that it can move with four degrees of freedom within thepatient's body.

While the present invention will be discussed with reference to theshaft portion 28 of laparoscopic tool 18, it will be appreciated that agreat number of other types of objects can be used with the method andapparatus of the present invention. In fact, the present invention canbe used with any elongated mechanical object where is desirable toprovide a human/computer interface with three or four degrees offreedom. Such objects may include catheters, hypodermic needles, wires,fiber optic bundles, screw drivers, pool cues, etc. Furthermore,although the described preferred embodiment of the present inventioncontemplates the use of a elongated cylindrical mechanical object, otherembodiments of the present invention provide a similar human/computerinterface for an elongated mechanical objects which are not cylindricalin shape.

The electronic interface 14 is a part of the human/computer interfaceapparatus 12 and coupled the apparatus 12 to the computer 16. Anelectronic interface 14 that is particularly well adopted for thepresent is described in U.S. patent application Ser. No. 08/092,974,filed Jul. 16, 1993, issued Nov. 19, 1996, as U.S. Pat. No. 5,576,727,and entitled "3-D Mechanical Mouse" assigned to the assignee of thepresent invention and incorporated herein by reference in its entirety.The electronic interface described therein was designed for theImmersion PROBE™ 3-D mechanical mouse and has six channels correspondingto the six degrees of freedom of the Immersion PROBE. However, in thecontext of the present invention, the electronic interface 14 requiresthe use of only four of the six channels, since the present invention ispreferably constrained to no more than four degrees of freedom.

The electronic interface 14 is coupled to a gimbal apparatus 25 of theapparatus 12 by a cable 30 and is coupled to the computer 16 by a cable32. In some embodiments of the present invention, interface 14 servessolely as an input device for the computer 16. In other embodiments ofthe present invention, interface 14 serves solely as an output devicefor the computer 16. In yet other embodiments of the present invention,the interface 14 serves as an input/output (I/O) device for the computer16.

In an alternative embodiment of the present invention, interface 14 hasa local microprocessor 33 preferably coupled with any transducerspresent in the interface 14 and with a transceiver 35. In such anembodiment, the computer 16 is coupled to the transceiver 35 and,typically, not coupled directly with any transducers present in theinterface 14. As will be appreciated, the transceiver 35 may be anysuitable transceiver capable of bi-directional communication throughserial or parallel communication strategies. The local microprocessor 33will be programmed to execute computer instructions locally such that acomputing burden is removed from the computer 16. For example,positional information generated by the transducers may be processedlocally by the local microprocessor 33, which in turn can send absoluteposition and velocity information to the computer 16.

In the perspective view of FIG. 2, the gimbal apparatus 25 of thepresent invention is illustrated in some detail. The gimbal apparatus 25includes a support 34 and a gimbal mechanism 36 rotatably coupled to thesupport. The gimbal mechanism 36 preferably includes a U shaped baseportion 38 including a base 40 and a pair of substantially parallel legs42a and 42b extending upwardly therefrom. As used herein, "substantiallyparallel" will mean that two objects or axis are exactly or almostparallel, i.e. are at least within five or ten degrees of parallel, andare preferably within less than one degree of parallel. Similarly, theterm "substantially perpendicular" will mean that two objects or axisare exactly or almost perpendicular, i.e. at least within five degreesor ten degrees of perpendicular, or more preferably within less than onedegree of perpendicular.

The gimbal mechanism 36 also includes an elongated object (shaft)receiving portion 44 provided with an aperture 46 which extends entirelythrough the object receiving portion. The aperture 46 defines an objectaxis A₀ for an elongated cylindrical object, such that the shaft portion28 of the laparoscopic tool 18 of FIG. 1. The object receiving portion44 is at least partially disposed between the legs 42a and 42b of the Ushaped base portion, and is pivotally coupled thereto such as by a pairof pivots, one of which is shown as pivot 48a in leg 42a. Another pivot48b (not shown) is provided in leg 42b.

The object receiving portion 44 also includes a translation interface 50and a rotation interface 52. The object receiving portion 44 includes abearing section 54, a translation sensor section 56, and a rotationsensor section 58. The bearing section 54 includes a mass of materialprovided with a cylindrical bore 60 forming a portion of the aperture46. The translation sensor section 56 includes a pair of opposing wallsurfaces 62a and 62b, each of which is provided with a cylindrical borereceptive to the cylindrical object and forming a part of the aperture46 which extends through the object receiving portion. The translationsensor section 56 includes a pair of opposing wall surfaces 64a and 64bof a wall 63 and which are provided with cylindrical bores receptive tothe cylindrical object and therefore also forming a part of the aperture46. In consequence, when an elongated cylindrical object is insertedinto the object receiving portion 44 along axis A₀ it engages the bore60 of the bearing section 54, and extends through bores provided in thesurfaces 62a, 62b, 64a, and 64b to extend completely through the objectreceiving portion 44 along the aperture 46. In another embodiment of thepresent invention, wall 63 (and therefore wall surfaces 64a and 64b) iseliminated as being superfluous.

Referring briefly to FIG. 2a, an alternative construction for thetranslation interface 50 of FIG. 2 is shown at 50'. This alternativetranslation interface 50' is well adapted for very thin shafts, wires,catheters, and the like. The problem encountered with the translationinterface 50 is that, for example, wires and catheters are flexible andtherefore do not engage well with a single friction wheel. Therefore,the translation interface 50' includes a drive wheel 65a that is coupledto a sensor and/or actuator, and an idler wheel 65b. The wire orcatheter 67 is pinched between the drive wheel 65a and the idler wheel65b so that there is good frictional engagement between the catheter 67and the drive wheel 65a.

The object receiving portion 44 is preferably a unitary mass of materialmade from aluminum or some other lightweight material such as a plastic.The object receiving portion 44 is preferably cast, molded, and/ormachined as a monoblock member having the aforementioned bearingsection, translation sensory section, and rotation sensory section. Thematerials and construction of U shaped base portion 38 preferably matchthe materials and construction techniques used for the production ofobject receiving portion 44.

The gimbal apparatus 25 illustrated in FIG. 2 constrains an object thatis engaged with the object receiving portion 44 to four degrees offreedom. This is accomplished by allowing the U shaped base portion 38to rotate around an axis A₁ relative to the support 34, by allowing theobject receiving portion 44 to rotate around an axis A₂ relative to theU shaped base portion 38, by allowing the object to translate asillustrated by the arrow t along axis A₀ of aperture 46, and by allowingthe object to rotate as indicated by arrow r around the axis A₀ ofaperture 46.

Four electromechanical transducers are used in association with thesefour degrees of freedom. Movie particularly, a first degree of freedomelectromechanical transducer 66 is arranged to transduce motion and/orforce between the U shaped base portion 38 and the support 34, a seconddegree of freedom electromechanical transducer 68 is arranged totransduce motion and/or force between the U shaped base portion 38 andthe object receiving portion 44, a third degree of freedomelectromechanical transducer 70 is arranged to transduce motion and/orforce between the object receiving portion 44 and an object engaged withthe object receiving portion 44, and a fourth degree of freedomtransducer 72 is arranged to transduce motion and/or force between theobject receiving portion 44 and an object engaged with the objectreceiving portion 44.

By "associated with", "related to", or the like, it is meant that theelectromechanical transducer is influenced by or influences one of thefour degrees of freedom. The electromechanical transducers can be inputtransducers, in which case they sense motion along a respective degreeof freedom and produce an electrical signal corresponding thereto forinput into computer 16. Alternatively, the electromechanical transducerscan be output transducers which receive electrical signals from computer16 that cause the transducers to impart a force on the object inaccordance with their respective degrees of freedom. Theelectromechanical transducers can also be hybrid or bi-directionaltransducers which operate both as sensors and as actuator devices.

A variety of transducers, readily available in the commercial market aresuitable for use in the present invention. For example, if thetransducers are input transducers ("sensors"), such sensors can includeencoded wheel transducers, potentiometers, etc. Output transducers("actuators") include stepper motors, servo motors, magnetic particlebrakes, friction brakes, pneumatic actuators, etc. Hybrid orbi-directional transducers often pair input and output transducerstogether, but may also include a purely bi-directional transducer suchas a permanent magnet electric motor/generator.

It should be noted that the present invention can utilize both absoluteand relative sensors. An absolute sensor is one which the angle of thesensor is known in absolute terms, such as with an analog potentiometer.Relative sensors only provide relative angle information, and thusrequire some form of calibration step which provide a reference positionfor the relative angle information. The sensors described herein areprimarily relative sensors. In consequence, there is an impliedcalibration step after system power-up wherein the shaft is placed in aknown position within the gimbal mechanism and a calibration signal isprovided to the system to provide the reference position mentionedabove. All angles provided by the sensors are thereafter relative tothat reference position. Such calibration methods are well known tothose skilled in the art and, therefore, will not be discussed in anygreat detail herein.

A preferred input transducer for use of the present invention is anoptical encoder model SI marketed by U.S. Digital of Vancouver, Wash.This transducer is an encoded wheel type input transducer. A preferredoutput transducer for use of the present invention is a d.c. motor model2434.970-50 produced by Maxon of Fall River, Mass. This type oftransducer is a servo motor type output transducer.

There a number of ways of attaching the transducers to the variousmembers of the gimbal apparatus 25. In this preferred embodiment, ahousing of transducer 66 is attached to the U shaped base portion 38,and a shaft of the transducer extends through an oversize bore (notshown) in base 40 to engage a press-fit bore (also not shown) in support34. Therefore, rotation of the U shaped base portion 38 around axis A₁will cause a rotation of a shaft of transducer 66. A housing oftransducer 68 is attached to leg 42a of the U shaped base portion 38such that its shaft forms pivot 48a. Therefore rotation of the objectreceiving portion 44 around axis A₂ will cause a rotation of the shaftof a second transducer 68. The transducer 70 is attached to objectreceiving portion 44 and extends through a bore (not shown) in a wall 74of the translation sensor section 56. The shaft 76 provides an axisabout which the translation interface 50 can rotate. The fourthtransducer 74 is attached to a wall 78 of rotation sensor section 58 andextends through a bore 80 in that wall 78. The shaft 82 of thetransducer 72 engages a circumferential surface of rotation interface 52and rotates therewith.

Axes A₁ and A₂ are substantially mutually perpendicular and intersect atan origin point O within object receiving portion 44. Axis A₀ alsointersects this origin O. Shaft 76 rotates around an axis A₃ which issubstantially perpendicular to the axis A₀. Shaft 58 of transducer 72rotates around an axis A₄ which is substantially parallel to the axisA₀.

In FIG. 3, a front view of the gimbal apparatus 25 is used to illustrateone of the degrees of motion of the laparoscopic tool 18. Theillustrated degree of freedom is the fourth degree of freedom, i.e.rotation around axis A₀ as illustrated by the arrow r in FIG. 2. Thisdegree of freedom is detected by transducer 72. In this fourth degree ofmotion, the handle portion 26 of the laparoscopic tool 18 can rotate ina clockwise direction as indicated at 26' and in a counter clockwisedirection as indicated at 26". Of course, the handle 26 can rotate afull 360° although this would require the release and re-grasping of thehandle 26.

In FIG. 4, a second degree of freedom is illustrated. With this degreeof freedom, the laparoscopic tool 18 can pivot upwardly as illustratedat 18' or downwardly (not shown). This rotation around A₂ is detected bytransducer 68. It should be noted in the present embodiment, thelaparoscopic tool 18 cannot rotate 360° around the axis A₂ because it isphysically constrained by the support 34, portions of the gimbalmechanism 36, etc. However, in the present embodiment, the laparoscopictool can achieve approximately 170 degrees of rotation around axis A₂.

FIG. 5 is top view of the gimbal apparatus 25 and illustrates the firstand third degrees of freedom. The first degree of freedom is detected bytransducer 66 as the laparoscopic tool 18 is pivoted or rotated aroundaxis A₁ as illustrated at 18a and 18b. The third degree of freedom isdetected by transducer 70 as the shaft portion 28 of laparoscopic tool18 is moved back and fourth as illustrated by the arrow "t." This causesa rotation of translation interface 50 and the shaft 76 of the thirdtransducer 70.

The four degrees of freedom are illustrated graphically in FIG. 6. Thecylinder 66' represents the first transducer 66 and allows a firstdegree of freedom labeled "1st" around axis A₁. Cylinder 68' representsthe sensor 68 and allows a second degree of freedom labeled "2nd" aroundaxis A₂. Telescoping members 70a' and 70b' represent the third sensor 70can sense movement along a third degree of freedom labeled "3rd" alongaxis A₀. Finally, a cylinder 72' attached to member 70b' represents thefourth transducer 72 and senses a fourth degree of freedom labeled "4th"around axis A₀. A member 84 is provided to indicate position androtational direction relative to axis A₀.

In FIG. 7, a preferred input transducer (sensor) of the presentinvention is disclosed. Again, an input transducer of this type can bepurchased as sensor model SI from U.S. Digital of Vancouver, Wash. Theinput transducer 86 includes a bearing block 88 having a bearing 89, arotary shaft 90 supported by the bearing 89, and a sensing wheel 92supported for rotation by shaft 90. The sensing wheel is preferably madefrom a clear, plastic material and is provided with a number of darkradial bands 94 near its circumference, such as by printing or silkscreening. A first photodetector pair 96a including a light source 98aand a detector 100a are positioned on opposing sides of the sensingwheel 92 in alignment with the bands 94. Similarly, a secondphotodetector pair 96b including a light source 98b and a detector 100bare positioned on opposing sides of the sensing wheel 92 in alignmentwith the bands 94. As the sensing wheel 92 rotates as illustrated at 102around an axis A, the bands 94 alternatively allow light emanating fromlight sources 98a and 98b to impinge or not impinge upon the detectors100a and 100b, respectively. The electronic interface 14, coupled to thephotodetector pairs 96a and 96b by cable 30, counts the bands 94 as theypass the photodetector pairs 96a and 96b to provide a signal on cable 32to the computer 16 indicating the rotational position of the shaft 90around axis A. The two pairs 96a and 96b are provided to determine thedirection of rotation, as is well known to those skilled in the art ofsensor design.

FIGS. 8 and 8a illustrate a modified laparoscopic tool 104. Moreparticularly, a sensor 106 has been added to determine when the handle108 has been squeezed, and the shaft 110 has been grooved or slotted fora purpose to be discussed subsequently. The sensor 106 can be coupled tothe computer 16 through electronic interface 14 to provide additionalinput to the virtual reality system.

With reference to FIG. 8a, the shaft 110 is preferably hollow, having anaxial bore 112 which aligns with axis A₀, and is provided with anelongated groove 114 which is parallel to an axis A_(L) of the shaft110. This elongated groove 114 can be produced by any process includingextruding the shaft 110 in the appropriate shape, or cutting the groove114 with a machine tool, etc.

FIGS. 9 and 9a illustrate an alternate embodiment for transducer 72which utilizes the shaft 110 and a detector mechanism similar to the oneillustrated in FIG. 7. More particularly, the transducer 72' includes asleeve 115 which is slidingly engaged with shaft 110. As seen in thecross sectional view of FIG. 9a, the sleeve 115 is a substantiallycylindrical object having a central bore 116 which engages thecircumference 118 of the shaft 110. The sleeve 115 has a key 120 whichengages the slot 114 of the shaft 110. Therefore, while the sleeve canslide back and forth along the axis A_(L) as indicated at 122, but thesleeve 115 rotates with the shaft 110 as indicated at 124 due to theengagement of the key 120 with the groove 114. A sensing wheel 92' isaffixed to a circumferential portion of sleeve 115 so that it rotatescoaxially with the sleeve 115. A photodetector pair 96' senses themotion of bands 94' and produces an electrical signal on cable 30. Theadvantage of the embodiment shown in FIG. 9 and 9a is that rotation ofthe shaft around axis A_(L) is detected without the possibility ofslippage. Another advantage of this embodiment is that it is morecompact in design.

In FIG. 9b an alternate embodiment for a rotation interface 52' isshown. This alternate embodiment is well adapted for flexible shafts,wires, catheters and the like, such as the aforementioned catheter 67.The rotation interface 52' includes a transducer 72"" that is providedwith a resilient grommet 73 having a hole that engages a circumferentialportion of the catheter 67. The grommet 73 is preferably a rubber orplastic grommet that causes the catheter 67 to rotate coaxially as thecatheter spins or rotates. Preferably, the mass of the transducer 72""is kept very small so that it only takes a small amount of friction toensure coaxial rotation of the catheter and transducer without slippage.Because the level of friction is so small, it does not substantiallyimpede translational motion (i.e. in-out motion) of the catheter.

FIGS. 10 and 10a illustrate another embodiment 72" for the transducer 72of FIG. 2. This embodiment has a number of points of similarity with theembodiment discussed with reference to FIGS. 9 and 9a, and it will beappreciated that elements with like reference numerals operate in asimilar fashion. However, the embodiment of FIGS. 10 and 10a include asheave 126 affixed to the circumference of sleeve 115 in the place ofthe sensing wheel 92' of FIG. 9 and FIG. 9a. A position sensor 128 has ashaft 130 which is coupled to the sheave 126 by a belt 132. The belt 132can be any continuous loop structure including a resilient, rubber-typebelt, a drive-chain type belt, etc. The shaft 130 of position sensor 128therefore rotates with the sheave 126. The advantage of using a belt 132or the like is that a substantial amount of force may be applied to thebelt to, again, minimize slippage.

Another embodiment 72'" for the fourth transducer is illustrated inFIGS. 11 and 11a. Again, there are a number of points of similaritybetween the embodiments of FIGS. 11 and 11a and the previously describedembodiments of FIGS. 9 and 9a and FIGS. 10 and 10a. Therefore, likereference numerals will again refer to like elements. In thisembodiment, a sensor 134 has a shaft 136 which serves as the axle of afriction wheel 138 which, in turn, engages a circumferential surface ofsleeve 115. Therefore, a rotation of the shaft 110 will cause a rotationof the sleeve 115, which will cause a rotation of the wheel 138 and theshaft 136 to create an electrical signal on cable 30.

With reference to all of the figures, and with particular reference toFIGS. 1 and 2, the shaft 28 of a laparoscopic tool 18 is inserted intoaperture 46 along axis A₀, causing the shaft 28 to frictionally engagethe translation interface (wheel) 50. In this instance, thetranslational interface 50 is a friction wheel made out of a rubber-likematerial. The shaft 28 is also in engagement with the rotation interface50 which, in the embodiment of FIG. 2, is also a friction wheel made outof a rubber-like material. Rotation of the shaft 28 around the axis A₀as illustrated by the arrow r will cause a rotation of the frictionwheel 50 and therefore the shaft 82 of the sensor 72. A translation ofthe shaft 28 along axis A₀ will cause a rotation of the friction wheel50 which rotates the shaft 76 of the transducer 70. A movement up ordown of the laparoscopic tool 18 will cause a rotation of the shaft(pivot) 48a of transducer 68, and a side-to-side pivoting of thelaparoscopic tool 18 will cause a rotational around axis A₁ which isdetected by transducer 66.

To this point, the majority of the discussion has been under theassumption that the transducers are input transducers, i.e. thehuman/computer interface device is used an input device to the computer16. However, it is also been mentioned that the interface device 12 canserve as an output device for the computer 16. When used as an outputdevice, output transducers ("actuators") are used to respond toelectrical signals developed by the computer 16 to impart a force uponthe shaft 28 of the laparoscopic tool 18. This can provide usefulmovement and force (haptic) feedback to the doctor/trainee or otheruser. For example, if the laparoscopic tool encounters dense mass oftissue or a bone in the "virtual" patient, a force can be generated bytransducer 70 making it harder for the doctor/trainee to push the shaft28 further into the gimbal apparatus 25. Likewise, twisting motions canbe imparted on the shaft 28 when the shaft encounters an obstacle withinthe virtual patient.

It should be noted that force applied to the shaft may not result in anymovement of the shaft. This is because the shaft may be inhibited frommovement by the hand of the operator who is grasping a handle or gripportion of the shaft. However, the force applied to the shaft may besensed by the operator as haptic feedback.

With reference to FIG. 2, a method for mechanically interfacing anelongated mechanical object with an electrical system in accordance withthe present invention includes first step of defining an origin in3-dimensional space. This corresponds to the origin O at theintersection of axis A₁ and A₂. A second step is to physically constrainan elongated object in the 3-dimensional space such that a portion ofthe object always intersects the origin O and such that a portion of theobject extending from the origin O defines a radius in a sphericalcoordinate system. The elongated object (such as shaft 28 oflaparoscopic tool 18) is physically constrained in a 3-dimensional spaceby the aperture 46 of the object receiving portion 44. The portion ofthe shaft 28 extending from origin O defines the radius. A third stepincludes transducing a first electrical signal related to a firstangular coordinate of the radius with a first transducer. Thiscorresponds to the operation of transducer 66 which transduces a firstelectrical signal related to a first angular coordinate of the radius. Afourth step is transducing a second electrical signal related to asecond angular coordinate of the radius. This corresponds to theoperation of transducer 68 which transduces a second electrical signal.A fifth step is to transduce a third electrical signal related to thelength of the radius, which corresponds to the operation of transducer70. A sixth and final step is to electrically couple the transducers toan electrical system which, in this instance, is preferably a computer16. An additional, optional step transduces a fourth electrical signalrelated to a rotation of the object around an object axis whichintersects the origin O. This step corresponds to the operation oftransducer 72. The transducers can be input transducers, outputtransducers, or bi-directional transducers.

It will be noted that the electrical system most frequently described inthe present invention is a digital processing system or a computer.However, other digital systems, analog systems, and simple electric orelectromechanical system can also be utilized with the apparatus andmethod of the present invention.

It will also be noted that while specific examples of "elongatedobjects" and "shafts" have been given, that these examples are not meantto be limiting. In general, equivalents of "elongated objects","elongated cylindrical objects", "shafts", etc. include any object whichcan be grasped by a human operator to provide an interface between theoperator and a computer system. By "grasp", it is meant that operatorsmay releasably engage a grip portion of the object in some fashion, suchas by hand, with their fingertips, or even orally in the case ofhandicapped persons. The "grip" can be a functional grip or handleattached to an elongated portion of the object, or can be a portion ofthe object itself, such as a portion of the length of a shaft that canbe gripped and/or manipulated by the operator.

It should also be noted that flexible shafts, such as wires orcatheters, do not always require three or four degrees of freedom. Forexample, if a human/computer interface for a catheter insertion virtualreality system is desired, only a translation interface (e.g.translation interface 50' of FIG. 2a) and rotation interface (such asrotation interface 52' of FIG. 9c) may be required. This is because acatheter can be moved in and out of a virtual patient (as sensed bytranslation interface 50') and can be twisted or rotated (as sensed byrotation interface 50'), but cannot be, in any practical manner, movedup or down or from side-to-side due to the flexibility of the catheter.In such applications, therefore, it is desirable to have ahuman/computer interface with only two degrees of freedom.

While this invention has been described in terms of several preferredembodiments, it is contemplated that alternatives, modifications,permutations and equivalents thereof will become apparent to thoseskilled in the art upon a reading of the specification and study of thedrawings. It is therefore intended that the following appended claimsinclude all such alternatives, modifications, permutations andequivalents as fall within the true spirit and scope of the presentinvention.

What is claimed is:
 1. A control input device for interfacing the motionof an elongated mechanical object with a computer system comprising:asupport; a gimbal mechanism having a base portion rotatably coupled tosaid support to provide a first degree of freedom, and an objectreceiving portion rotatably coupled to said base portion to provide asecond degree of freedom; a first degree of freedom electromechanicaltransducer arranged to sense rotation between said support and said baseportion; a second degree of freedom electromechanical transducerarranged to sense rotation between said base portion and said objectreceiving portion; a third degree of freedom electromechanicaltransducer arranged such that when an elongated object is at leastpartially disposed within said object receiving portion, said thirddegree of freedom transducer is arranged to transduce motion betweensaid object receiving portion and said elongated object, said thirddegree of freedom transducer further operable to sense lineardisplacement of said object with respect to said object receivingportion without causing substantial linear displacement of said objectreceiving portion with respect to said support; and a fourth degree offreedom electromechanical transducer arranged such that when saidelongated object is at least partially disposed within said objectreceiving portion, said fourth degree of freedom transducer transducesmotion between said object receiving portion and said elongated object,said fourth degree of freedom transducer being a rotational transduceroperable to sense rotational motion of said object with respect to saidobject receiving portion without causing substantial rotational motionin said object receiving portion with respect to said support; whereinsaid support, said gimbal mechanism, said object receiving portion, andsaid electromechanical transducers are arranged such that when saidelongated object is at least partially disposed within said objectreceiving portion, said elongated object is constrained to at most fourdegrees of freedom of motion with respect to said support, and wherebysaid transducers are operable to provide an electromechanical interfacebetween said elongated object and a digital processing system.
 2. Acontrol input device as recited in claim 1 wherein said base portionrotates around a first axis and said object receiving portion rotatesaround a second axis that is substantially perpendicular to said firstaxis, and wherein said elongated object defines a radius in a sphericalcoordinate system having an origin at an intersection of said first axisand said second axis.
 3. A control input device as recited in claim 1wherein said transducers include at least one actuator which imparts amovement to said object along their respective degree of freedom inresponse to electrical signals produced by said digital processingsystem.
 4. A control input device as recited in claim 1 furtherincluding:a local microprocessor coupled to said sensors and operable tocommunicate with said sensors; and a transceiver coupled to said localmicroprocessor, said transceiver operable to communicate informationbetween said local microprocessor and a device external to saidapparatus coupled with said transceiver.
 5. A human/computer interfacecontrol input device comprising:an apparatus for interfacing the motionof an elongated mechanical object as recited in claim 4; and an externalhost computer coupled to said transceiver such that said external hostcomputer and said local microprocessor may communicate, said externalhost computer executing a simulation responsive to communication fromsaid local microprocessor such that a simulated object representing saidelongated object within a simulated environment has a simulated positionand a simulated orientation correlated to a position and an orientationof said elongated object.
 6. A control input device as recited in claim1 wherein said third degree of freedom transducer includes a translationwheel having a translation wheel axis that is substantiallyperpendicular to said object axis, said translation wheel contacting asurface of said cylindrical object when said cylindrical object isengaged with said aperture of said receiving portion such that atranslation of said cylindrical object along said object axis causes arotation of said translation wheel.
 7. A control input device as recitedin claim 6 wherein said translation wheel is coupled to a rotationalposition sensor which provides, at least in part, said third inputelectrical signal.
 8. A control input device as recited in claim 1wherein said fourth degree of freedom transducer includes a rotationwheel having a rotation wheel axis which is substantially parallel tosaid object axis, said rotation wheel being coupled to said cylindricalobject to rotate therewith.
 9. A control input device as recited inclaim 8 wherein said rotation wheel is coupled to a rotational positionsensor which provides, at least in part, said fourth input electricalsignal.
 10. A control input device as recited in claim 8 wherein saidrotation wheel contacts a surface of said cylindrical object when saidcylindrical object is engaged with said aperture of said receivingportion.
 11. A control input device as recited in claim 8 wherein saidcylindrical object is provided with an elongated slot substantiallyparallel to said object axis, and further comprising a sleeve having abore which forms a portion of said aperture and which has a key whichengages said slot of said cylindrical object such that said cylindricalobject may translate within said sleeve and such that said sleeverotates with said cylindrical object, said wheel being coupled to saidsleeve for rotation therewith.
 12. A control input device as recited inclaim 11 wherein said wheel forms a portion of a rotational positionsensor which provides, at least in part, stud fourth input electricalsignal.
 13. A control input device as recited in claim 11 wherein saidwheel comprises a sheave, and further including a rotational positionsensor having a shaft, said rotational position sensor providing, atleast in part, said fourth input electrical signal, and a continuousloop which engages both said sheave and said shaft such that said shaftof said rotational position sensor rotates with said cylindrical object.14. A control input device for interfacing the motion of an elongatedcylindrical mechanical object with a digital processing systemcomprising:a support; a gimbal mechanism including:a) a U shaped baseportion having a base and a pair of substantially parallel legsextending therefrom, wherein said base of said U shaped base portion isrotatably coupled to said support; and b) an elongated object receivingportion provided with an aperture extending therethrough which definesan object axis for an elongated cylindrical object, where said receivingportion is at least partially disposed between said legs of said Ushaped base portion and is pivotally coupled thereto, said receivingportion further including a translation interface and a rotationinterface, both disposed proximate to said object axis such that theyengage said elongated cylindrical object when it is engaged with saidaperture; wherein said base portion rotates around a first axis and saidobject receiving portion rotates around a second axis substantiallyperpendicular to said first axis, and wherein said object axis defines aradius in a spherical coordinate system having an origin at anintersection of said first axis and said second axis; a first inputtransducer arranged to transduce motion between said support and said Ushaped base portion to produce a first input electrical signalrepresentative of a sensed position of said U shaped base portionrelative to said support; a second input transducer arranged totransduce motion between said U shaped base portion and said objectreceiving portion to produce a second input electrical signalrepresentative of a sensed position of said object receiving portionrelative to said U shaped base portion; a third input transducer coupledto said translation interface to produce a third input electrical signalrepresentative of a sensed translation of said elongated cylindricalobject relative to said object receiving portion without causingsubstantial translational motion of said object receiving portion withrespect to said support; and a fourth input transducer coupled to saidrotation interface and said object to produce a fourth input electricalsignal representative of a sensed rotation of said elongated cylindricalobject relative to said object receiving portion without causingsubstantial rotational motion of said object receiving portion withrespect to said support.
 15. A control input device as recited in claim14 further comprising:a first actuator coupled between said support andsaid U shaped base portion to produce a force on said U shaped baseportion with respect to said support in response to a first outputelectrical signal; a second actuator coupled between said U shaped baseportion and said object receiving portion to produce a movement of saidobject receiving portion with respect to said U shaped base portion inresponse to a second output electrical signal; and a third actuatorcoupled to said translation interface to produce force along saidelongated cylindrical object with respect to said object receivingportion in response to a third output electrical signal actuator coupledto said rotation interface to produce a rotational movement of saidelongated cylindrical object with respect to said object receivingportion in response to a fourth output electrical signal.
 16. A controlinput device as recited in claim 15 further comprising a fourth actuatorcoupled to said rotation interface to produce a rotational movement ofsaid elongated cylindrical object with respect to said object receivingportion in response to a fourth output electrical signal.
 17. A methodfor interfacing movements of an elongated mechanical object with adigital processing system comprising the steps of:defining an origin ina 3-dimensional space; physically constraining an elongated object insaid 3-dimensional space such that a portion of said object alwaysintersects said origin and such that a portion of said object extendingfrom said origin defines a radius in a spherical coordinate system;transducing a first electrical signal related to a first angularcoordinate of said radius in said spherical coordinate system with afirst sensor means; transducing a second electrical signal related to asecond angular coordinate of said radius in said spherical coordinatesystem with a second sensor means; transducing a third electrical signalrelated to the length of said radius with a third sensor means;transducing a fourth electrical signal related to a rotation of saidobject around an object axis which intersects said origin with a fourthsensor means; and electrically coupling said transducers to anelectrical system.
 18. A method as recited in claim 17 wherein anactuator is arranged to impart force on said object along a degree offreedom which one of said first, second, third, or fourth sensor meanssenses.
 19. A human/computer interface control input devicecomprising:an electromechanical interface for interfacing motion of anelongated object with a host computer system, said electromechanicalinterface including:a support; a gimbal mechanism having a base portionrotatably coupled to said support, and an object receiving portionrotatably coupled to said base portion, said elongated object engagedwith said object receiving portion, said object having a grip area to begrasped by a hand of an operator; a first sensor arranged to transducemotion between said support and said base portion, said first sensorhaving a first output; a second sensor arranged to transduce motionbetween said base portion and said object receiving portion, said secondsensor having a second output; a third sensor coupled between saidobject receiving portion and said object, said third sensor having athird output; a local microprocessor coupled to said sensors, said localmicroprocessor operable to receive and process said first, second andthird outputs; and a transceiver coupled to said local microprocessor,said transceiver operable to communicate information between said localmicroprocessor and a device external to said electromechanical interfacecoupled with said transceiver; whereby said first output, said secondoutput, and said third output correspond to three degrees of motion ofsaid elongated object as manipulated by said operator; and an externalhost computer coupled to said transceiver such that said external hostcomputer and said local microprocessor may communicate, said externalhost computer executing a simulation responsive to communication fromsaid local microprocessor such that a simulated object representing saidelongated object within a simulated environment has a simulated positionand a simulated orientation corresponding to a position and anorientation of said elongated object.
 20. A control input device asrecited in claim 19 wherein said base portion rotates around a firstaxis and said object receiving portion rotates around a second axis thatis substantially perpendicular to said first axis, and wherein saidelongated object defines a radius in a spherical coordinate systemhaving an origin at an intersection of said first axis and said secondaxis.
 21. A control input device as recited in claim 19 furthercomprising a fourth sensor coupled between said object receiving portionand said elongated object, said fourth sensor having a fourth outputcoupled to said local microprocessor and corresponding to a fourthdegree of motion of said elongated object as it is manipulated by saidoperator.
 22. A control input device as recited in claim 21 wherein saidthird sensor is a translation sensor, and wherein said fourth sensor isa rotation sensor.
 23. A control input device as recited in claim 22further comprising at least one actuator having an input, said at leastone actuator arranged between one of (i) said support and said baseportion, (ii) said base portion and said object receiving portion, and(iii) said object receiving portion and said object.
 24. A control inputdevice as recited in claim 22 further comprising:a first actuatorcoupled between said support and said base portion, said first actuatorhaving a first input; a second actuator coupled between said baseportion and said object receiving portion, said second actuator having asecond input; a third actuator coupled between said object receivingportion said object, said third actuator having a third input; whereinsaid first input, said second input, and said third input are coupled tosaid local microprocessor, and correspond to three degrees of motion ofsaid elongated object as said elongated object exerts a force againstsaid operator's grasp.
 25. A control input device as recited in claim 24wherein said first sensor and said first actuator are combined, saidsecond sensor and said second actuator are combined, said third sensorand said third actuator are combined, and said fourth sensor and saidfourth actuator are combined.
 26. A human/computer interface controlinput device comprising:an electromechanical interface for interfacingmotion of elongated, flexible shafts with a host computer system, saidelectromechanical interface including:a shaft receiving portion; anelongated, flexible shaft engaged with said shaft receiving portion,said flexible shaft having a grip area to be grasped by a hand of anoperator; a first sensor coupled to said shaft receiving portion and afirst intermediate portion of said shaft to detect translationalmovement of said shaft relative to said shaft receiving portion, saidfirst sensor having a first output; a second sensor coupled to saidshaft receiving portion and a second intermediate portion of shaft todetect rotational movement of said shaft relative to said shaftreceiving portion, said second sensor having a second output; a localmicroprocessor coupled to said sensors, said local microprocessoroperable to receive and process said first and second outputs; and atransceiver coupled to said local microprocessor, said transceiveroperable to communicate information between said local microprocessorand a device external to said electromechanical interface coupled withsaid transceiver; whereby said first output and second output correspondto two degrees of motion of said elongated object as manipulated by saidoperator; and an external host computer coupled to said transceiver suchthat said external host computer and said local microprocessor maycommunicate, said external host computer executing a simulationresponsive to communication from said local microprocessor such that asimulated object representing said elongated flexible shaft within asimulated environment has a simulated position and a simulatedorientation corresponding to a position and an orientation of saidflexible shaft.
 27. A control input device as recited in claim 26wherein said electromechanical interface further includes local memoryaccessible by said local microprocessor.
 28. A control input device asrecited in claim 26 wherein said flexible shaft is selected from thegroup consisting of wires and catheters.
 29. A control input device asrecited in claim 19 wherein said simulated object is a surgical tool.30. A control input device as recited in claim 19 wherein said elongatedobject represents a portion of a surgical tool handle.
 31. A controlinput device as recited in claim 30 wherein said surgical tool handle isa laparoscopic tool handle.
 32. A control input device as recited inclaim 31 wherein said elongated object includes a fifth transduceroperable to transduce an open-close motion of a manual grip of thelaparoscopic tool handle.
 33. A control input device as recited in claim24 wherein said microprocessor is operable to actuate said actuators inresponse to an appropriate communication from said external hostcomputer.
 34. A control input device as recited in claim 24 wherein saidfirst actuator is a motor.
 35. A control input device as recited inclaim 24 wherein said elongated object represents a portion of asurgical tool handle.
 36. A control input device as recited in claim 24wherein said elongated object represents a portion of a pool cue.
 37. Acontrol input device as recited in claim 24 further comprising a fourthactuator coupled between said object receiving portion and said object,said fourth actuator having a fourth input, said fourth input coupled tosaid local microprocessor and corresponding to a fourth degree of motionof said elongated object as said elongated object exerts a force againstsaid operator's grasp.
 38. A control input device as recited in claim 33wherein said external host computer executes commands in response tomovement of the elongated object such that a simulation of aninteraction between a surgical tool and biological tissue is achieved,whereby the user manipulating said elongated object will feel a forceassociated with said surgical tool and biological tissue interactionsimulation.
 39. A control input device as recited in claim 19 whereinthe object receiving portion includes a representation of a trocar. 40.A control input device as recited in claim 22 wherein said rotationsensor is engaged by a keyed slot in said elongated object.
 41. Acontrol input device as recited in claim 19 wherein said rotation sensoris engaged by frictional contact with said elongated object.
 42. Acontrol input device as recited in claim 19 wherein said rotationalsensor is engaged by a pulley which is engaged on a sleeve which is alsoengaged with said elongated object by way of a keyed slot in saidelongated object.
 43. A control input device apparatus as recited inclaim 19 wherein said gimbal mechanism is mounted substantially inside aphysical model of a human body.
 44. A control input device as recited inclaim 19 wherein said transceiver is a serial interface.
 45. A controlinput device as recited in claim 19 wherein said electromechanicalinterface further includes local memory accessible by said localmicroprocessor.
 46. A control input device as recited in claim 45wherein said local memory contains programming instructions for enablingcommunications between said local microprocessor and said external hostcomputer.
 47. A control input device as recited in claim 19 wherein saidexternal host computer further includes a computer display coupledtherewith and said external host computer is operable to display saidsimulated environment including said simulated object.
 48. A controlinput device for interfacing motion of an elongated object with a hostcomputer system, said control input device including:a support; a gimbalmechanism having a base portion rotatably coupled to said support, andan object receiving portion rotatably coupled to said base portion; afirst sensor means arranged to sense motion between said support andsaid base portion; a second sensor means arranged to sense motionbetween said base portion and said object receiving portion; a thirdsensor means arranged such that when said elongated object is at leastpartially disposed within said object receiving portion, said thirdsensor means is operable to sense linear motion of said elongated objectwith respect to said object receiving portion; a local microprocessorcoupled to said sensor means, said local microprocessor operable tocommunicate with said sensor means; and a transceiver coupled to saidlocal microprocessor, said transceiver operable to transmit informationbetween said local microprocessor and a device external to saidelectromechanical interface coupled with said transceiver.